#include<iostream>
using namespace std;

int main()
{
    int suma;
    int n;
    int cant;
    string opc = "si";


    while (opc== "si")
    {
        cin>>n;
        suma=0;
        cant=0;
        while(n!=0)
        {
            suma+=n;
            cant++;
            cin>>n;
        }
        cout<<suma/cant<<endl;
    }
    return 1;

}
